EP0014845A1 - Process for the preparation of urethanes - Google Patents

Process for the preparation of urethanes Download PDF

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Publication number
EP0014845A1
EP0014845A1 EP80100271A EP80100271A EP0014845A1 EP 0014845 A1 EP0014845 A1 EP 0014845A1 EP 80100271 A EP80100271 A EP 80100271A EP 80100271 A EP80100271 A EP 80100271A EP 0014845 A1 EP0014845 A1 EP 0014845A1
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Prior art keywords
compounds
palladium
iron
reaction
organic
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German (de)
French (fr)
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EP0014845B1 (en
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Robert Dr. Becker
Johann Dr. Grolig
Cristian Dr. Rasp
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Bayer AG
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Bayer AG
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
    • B01J23/8906—Iron and noble metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/06—Halogens; Compounds thereof
    • B01J27/08—Halides
    • B01J27/10—Chlorides

Definitions

  • the present invention relates to an improved process for the preparation of urethanes (carbamic acid esters) by reacting organic nitro compounds with carbon monoxide and organic compounds containing at least one hydroxyl group in the presence of palladium and / or palladium compounds and a cocatalyst which consists of a mixture of one or more iron oxides and / or Iron oxide hydrates and activating chloride-containing additives.
  • Organic isocyanates are generally produced on an industrial scale by reacting the corresponding amines with phosgene. Because of the toxicity of the phosgene, efforts have been made for some time to find an industrially feasible synthetic route to organic isocyanates in which the use of the phosgene is unnecessary. Such a synthetic route consists in the reaction of organic nitro compounds with carbons monoxide and organic hydroxyl compounds to give the corresponding urethanes and their subsequent cleavage into compounds having isocyanate and hydroxyl groups, it also being possible to modify the urethane obtained as an intermediate before the cleavage.
  • oxides and Oxide hydrates of divalent and trivalent iron can be used in pure form or as a mixture, such as, for example, iron (II) oxide, iron (II) hydroxide, iron (III) hydroxide, ⁇ -Fe 2 O 3 , ⁇ -Fe 2 O 3 , Fe 3 O 4 , ⁇ -FeO-OH, ⁇ -Fe0-OH, ⁇ -FeO-OH.
  • Be - are Sonder preferably the oxides and hydrated oxides of trivalent iron.
  • the oxidic iron component is used in concentrations of 0.1 to 20% by weight, preferably 1-5% by weight, based on the reaction mixture, including any solvents that may be used.
  • chlorine-containing compounds containing elements of the third to fifth main group or the first to eighth subgroup of the periodic table of elements with the exception of iron oxychloride, which may also be present as complex salts and / or hydrochlorides of, are chlorine-bonded chlorine tertiary organic amines used.
  • Particularly suitable hydrochlorides of tertiary amines are hydrochlorides of any tertiary amines having a molecular weight of 59-10,000, preferably 59-300, which are inert under the reaction conditions. There are both hydrochloride aliphatic and cycloaliphatic, aromatic araliphatic or heterocyclic tert. Suitable amines. Hydrochlorides of tert.
  • Amines which have substituents which are inert under the reaction conditions such as, for example, halogen, alkenyl, cyano, aldehyde, alkoxy, phenoxy, thioalkoxy, thiophenoxy, carbamyl, carboalkoxy and / or thiocarbamyl substituents.
  • tertiary amines examples include trimethylamine, triethylamine, triprcpylamine, tributylamine, cycloaliphatic tertiary amines, such as N, N-dimethylcyclohexylamine, N, N-diethylcyclohexylamine, 1,4-diazabicyclo (2,2,2) oetane, aromatic tertiary amines such as N, N-dimethylaniline, N, N-diethylaniline, and heteroaromatic tertiary amines such as pyridine, quinoline, isoquinoline, quinaldine, lepidine, pyrolyzed polyacrylonitrile or polyvinylridine.
  • the cocatalyst components (ii) are advantageously added in concentrations of 0.05 to 10% by weight, in particular 0.1 to 5% by weight, based on the reaction mixture, including any solvent which may be used set.
  • the pure compounds can be used, but mixtures of the compounds mentioned by way of example can also be used.
  • the essential catalyst components are palladium salts of the type exemplified below, which are preferably added as such to the reaction mixture.
  • Metallic palladium can also be added to the reaction mixture, since the chloride-activated iron oxide causes oxidation of the metallic palladium in palladium (II) compounds.
  • an inert carrier for example an aluminum oxide carrier for the palladium, is also conceivable.
  • Palladium is particularly advantageously added as a compound soluble in the reaction mixture.
  • Examples of compounds include palladium chloride, palladium bromide, palladium iodide, sodium tetrachloropalladate, potassium tetrachloropalladate, sodium tetrabromopalladate, sodium tetraiodopalladate, potassium tetraiodopalladate, palladium acetate, palladium acetylacetonate and the like.
  • soluble palladium compounds suitable.
  • a particularly preferred palladium salt is palladium chloride.
  • Palladium or the palladium compounds are preferably in concentrations, based on the reaction mixture, including any solvent used, from 0.0001 to 0.1% by weight, in particular from 0.0002 to 0.01% by weight, calculated as metallic palladium, admitted.
  • the reaction rate becomes too slow at lower palladium concentrations. Higher palladium concentrations are possible, but uneconomical due to the possible loss of precious metals, especially since the urethane yields are no longer increased. It is just one of the main advantages of the invention Process that allows the production of urethanes in excellent yields while using only extremely small amounts of palladium compounds.
  • bases preferably tertiary amines
  • tertiary amines are also used as further catalyst components. This concomitant use of tertiary amines increases the selectivity with regard to possible undesirable side reactions of the organic hydroxy compounds used as reactants.
  • Suitable organic bases are in particular any tert, inert under the reaction conditions.
  • tertiary amines examples include trimethylamine, triethylamine, tripropylamine, tributylamine and the like, cycloaliphatic tertiary amines such as N , N -dimethylcyclohexylamine, N, N-diethylcyclohexylamine, 1,4-diazabicyclo (2,2,2) octane and the like.
  • Aromatic tertiary amines such as N, N-dimethylaniline, N, N-diethylaniline, and heteroaromatic tertiary amines such as pyridine, quinoline, isoquinoline, quinaldine, lepidine, pyrolyzed polyacrylonitrile or polyvinylpyridine.
  • the tertiary amines can be added in concentrations of 0.01 to 10% by weight, in particular 0.1 to 5% by weight, based on the reaction mixture, including any solvent used.
  • Starting compounds for the process according to the invention are any organic nitro compounds, i.e. any nitro groups, otherwise organic compounds which are inert under the conditions of the process according to the invention and have at least one aliphatic, cycloaliphatic and / or aromatic nitro group, a molecular weight generally between 61 and 400, preferably 123 and 262, and any organic compounds containing at least one hydroxyl group Compounds, for example substituted or unsubstituted, aliphatic, cycloaliphatic and / or aromatic mono- or polyhydroxy compounds, of a molecular weight generally between 32 and 228, preferably 32 and 102.
  • aromatic nitro compounds can be used: nitrobenzene, o-dinitrobenzene, m-dinitrobenzene, p-dinitrobenzene, o-chloro-nitrobenzene, m-chloro-nitrobenzene, o-chloro-nitrobenzene, o-nitrotoluene, m-nitrotoluene, p- nitrotoluene, 2,3-dinitrotoluene, 2,4-Dinitrotolüol, 2,5-dinitrotoluene, 2,6-D initrotoluol, 3,4-dinitrotoluene, 3-nitro-o-xylene, 4-nitro-o-xylene, 2 -Nitro-m-xylene, 4-nitro-m-xylene, 5-nitro-m-xylene, nitro-p-xylene, 3,4-dinitro-o-xylene, 3,5-dinitro-
  • cycloaliphatic nitro compounds nitrocyclobutane, nitrocyclopentane, nitrocyclohexane, 1,2-dinitracyclohexane, 1,3-dinitrocyclohexane, 1,4-dinitrocyclohexane, bis- (nitrocyclohexyl) methane.
  • nitroalkanes examples include: nitromethane, nitroethane, 1-nitropropane, 2-nitropropane, nitrobutane, nitropentane, nitrohexane, nitrodecane, nitrocetane, 1,2-dinitroethane, 1,2-dinitropropane, 1,3-dinitropropane, dinitrobutane , Dinitropentane, Dinitrohexane, Dinitrodecane, Phenylnitromethan, Bis- (nitromethyl) -cyclohexane, Bis- (nitromethyl) -benzenes, ⁇ -Nitrocarbonsonitrile.
  • nitro compounds for the process according to the invention are aromatic nitro compounds such as in particular nitrobenzene, 1,3-dinitrobenzene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, dinitronaphthalenes such as e.g. 1,5-dinitronaphthalene or 2,4'- or 4,4'-dinitrodiphenylmethane.
  • Organic compounds containing hydroxyl groups suitable according to the invention include monovalent ones Alcohols, polyhydric alcohols, monohydric phenols and polyhydric phenols.
  • the alcohols include linear or branched alkanols, cycloalkanols, alkenols, cycloalkenols, aralkyl alcohols and the like, each mono- or polyvalent. These alcohols may contain a substituent containing oxygen, nitrogen, sulfur or a halogen atom, for example a halogen, sulfoxide, sulfone, amine, amide, carbonyl or carboxylic acid ester group.
  • the following monohydric alcohols may be mentioned by way of example: methyl alcohol, ethyl alcohol, propanol, isopropanol, butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol.
  • Suitable polyhydric alcohols are, for example: ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerol, hexanetriol and the like, and more highly functional polyols. Monohydric aliphatic alcohols with 1-6 carbon atoms are preferred, and ethyl alcohol is particularly preferred.
  • the phenols suitable according to the invention include, for example, phenol, chlorophenols, cresols, ethylphenols, propylphenols, butylphenols or higher alkylphenols, pyrocatechol, resorcinol, 4,4'-dihydroxydiphenylmethane, bisphenol-A, anthranol, phenanthrol, pyrogallol or phloroglucin.
  • the organic hydroxy compounds are generally carried out when carrying out the process according to the invention mean used in such amounts that when using mononitro compounds as the starting material an equivalent ratio between nitro groups and hydroxyl groups of 1: 0.5 to 1: 100, preferably 1: 1 to 1: 100 and when using dinitro compounds an equivalent ratio between nitro groups and hydroxyl groups of 1: to 1: 100 is present.
  • the preferred alcohols are particularly preferably used in excess, the unreacted excess serving as the reaction medium.
  • the carbon monoxide is generally used in an amount corresponding to 1 to be converted nitro groups to 30 moles of carbon monoxide per M ol, being pressed in general, the carbon monoxide in the preferably used in the present process pressure reactor.
  • the reaction according to the invention can be carried out in the presence or in the absence of a solvent.
  • the organic hydroxyl compound which is preferably used in excess, serves as the solvent.
  • the amount of the solvent irrespective of whether it is an excess hydroxyl compound or an inert solvent, must be such that that the heat of reaction of the exothermic urethane formation can be dissipated without undue increase in temperature.
  • the process according to the invention is therefore carried out using a concentration of nitro compounds of 5-30% by weight, preferably 5-20% by weight, based on the total reaction mixture including the solvent.
  • solvents which are inert to the reaction components and the catalyst system, such as aromatic, cycloaliphatic and aliphatic hydrocarbons, which may optionally be substituted by halogen, such as benzene, toluene, xylene, chlorobenzene, dichlorobenzene, trichlorobenzene, chloronaphthalene, cyclohexane, methylcyclohexane, chlorine Methylene chloride, carbon tetrachloride, carbon tetrachloride, trichlorotrifluoroethane and the like Links.
  • halogen such as benzene, toluene, xylene, chlorobenzene, dichlorobenzene, trichlorobenzene, chloronaphthalene, cyclohexane, methylcyclohexane, chlorine Methylene chloride, carbon tetrachloride, carbon tetrachloride, trichlorotrifluoro
  • the reaction temperature is generally between 100 ° C. and about 300 ° C., in particular between 1300 ° C. and 250 ° C. and particularly advantageously in the range from 140 ° C. to 220 ° C.
  • the pressure must be such that the presence of a liquid phase is always ensured and is generally in the range from 5 to 500 bar, particularly advantageously in the range from 30 to 300 bar at the reaction temperature.
  • the amount for quantita Reactive sales required reaction time between a few minutes and several hours.
  • reaction of the nitro compounds with the hydroxy compounds and carbon monoxide to form urethanes can be carried out batchwise or continuously.
  • the batchwise reaction can be carried out in a high-pressure autoclave with small amounts of homogeneously dissolved palladium salt, a sufficient excess of iron oxide and / or iron oxide hydrate and a sufficient amount of the cocatalyst components (ii) mentioned by way of example.
  • the iron oxides or iron oxide hydrates which are insoluble in the reaction medium are preferably added in the form of a fine powder, the activating additives (ii) preferably in the form of a homogeneous alcoholic solution.
  • the undissolved excess iron oxide compounds can be distributed, for example, by vigorous stirring or by pumping around the reaction mixture.
  • the exothermic heat of reaction can be dissipated, for example, by internally installed cooling units or, in the case of pumping, by an external heat exchanger.
  • the work-up and recycling of the catalyst can take place in various ways depending on the solubility of the urethane produced in the reaction mixture.
  • slightly soluble urethanes the majority of the poorly soluble at low temperatures Kokatalysatorgemisches together with the greatest part of the Adsor example, after completion of the reaction - based palladium and the organic amine salt are separated from the reaction product, for example by filtration or centrifugation, and are recycled into a new reaction of nitro compounds, hydroxy compounds and carbon monoxide.
  • the liquid reaction mixture can be separated in a customary manner, for example by fractional distillation, in solvent, into the pure urethanes and, if appropriate, small amounts of by-products, which separation can be carried out batchwise or continuously.
  • the distillation residue often contains small amounts of the cocatalyst component (ii) dissolved in the reaction mixture and / or traces of palladium compounds, which can be returned to the reaction.
  • the reaction mixture can be worked up in a modified manner. For example, after relaxation under pressure and a higher temperature, at which the urethanes are still dissolved, but the catalyst system palladium / cocatalyst mixture largely fails, the main amount of catalyst is filtered off or centrifuged and then the sparingly soluble urethane, if appropriate together with small amounts of sparingly soluble by-products and the rest, is reduced by lowering the temperature Catalyst crystallized out.
  • the mother liquor, in addition to solvents, or the excess organic hydroxy compound used as solvent, still small amounts of by-products, ge contains dissolved urethane and optionally dissolved cocatalyst components (ii) can be recycled directly or after the removal of low-boiling by-products, for example by distillation, into the reaction of the nitro compounds with the hydroxy compounds and carbon monoxide, which is supplemented by the amount of nitro compound and hydroxy compound corresponding to the previous conversion .
  • Higher-boiling by-products which are not removed by crystallization can be continuously removed from the recycle stream as a distillation residue by working up an aliquot of the mother liquor by distillation.
  • the precipitated crude urethane can be recrystallized, for example, by crystallization from a solvent which dissolves the urethane at higher temperatures but does not dissolve the by-products and the catalyst residues, such as isooctane, benzene, toluene, xylene, chlorobenzene, dichlorobenzene.
  • the residues which are insoluble at elevated temperature can be converted by oxidation into iron oxide and a waste gas resulting from the organic impurities, which essentially consists of carbon dioxide, oxygen, nitrogen and optionally highly volatile organic impurities.
  • the exhaust gas can be discharged directly into the atmosphere or additionally fed to a catalytic post-combustion, in which residual impurities are removed by oxidation. That from the Residue obtained iron oxide, which may still contain small amounts of palladium and / or palladium compound, is returned to the reaction of the nitro compounds with hydroxy compounds and carbon monoxide.
  • the continuous reaction can be carried out in a boiler cascade, a tube bundle reactor, a plurality of loop reactors connected in series, in one or a series of adiabatic reaction tubes connected in series.
  • the heat is dissipated, for example, either internally through built-in cooling units, externally via a tube bundle heat exchanger, or adiabatically via the heat capacity of the reaction mixture with subsequent cooling in external cooling units.
  • This experiment demonstrates the need to activate the ⁇ -Fe 2 O 3 with a chloride additive (for example in the form of FeCl 2 ⁇ 4 H 2 0 or pyridinium chloride).
  • a chloride additive for example in the form of FeCl 2 ⁇ 4 H 2 0 or pyridinium chloride.

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Abstract

[* und Palladiumchlorid.] Die vorliegende Erfindung betrifft ein neues Verfahren zur Herstellung von Urethanen durch Umsetzung organischer Nitroverbindungen mit Kohlenmonoxid und mindestens eine Hydroxygruppe enthaltenden organischen Verbindungen in Gegenwart von Palladium und/oder Palladium-Verbindungen und einem Kokatalysator, wobei man als Kokatalysator sowohl (i) Eisenoxide und/oder Eisenoxidhydrate als auch (ii) anionisch, als Chlorid gebundeses Chlor enthaltende Verbindungen von Elementen der dritten bis fünften Hauptgruppe oder ersten bis achten Nebengruppe des Periodensystems der Elemente mit Ausnahme von Eisenoxychlorid[*] und/oder tert. Ammoniumchloride einsetzt.[* and palladium chloride.] The present invention relates to a new process for the production of urethanes by reacting organic nitro compounds with carbon monoxide and organic compounds containing at least one hydroxyl group in the presence of palladium and / or palladium compounds and a cocatalyst. i) iron oxides and / or iron oxide hydrates as well as (ii) anionic compounds containing chlorine bound chlorine of elements of the third to fifth main group or first to eighth subgroup of the periodic table of the elements with the exception of iron oxychloride [*] and / or tert. Ammonium chloride used.

Description

Die vorliegende Erfindung betrifft ein verbessertes Verfahren zur Herstellung von Urethanen (Carbamidsäureestern) durch Umsetzung organischer Nitroverbindungen mit Kohlenmonoxid und mindestens eine Hydroxygruppe enthaltenden organischen Verbindungen in Gegenwart von Palladium und/oder Palladiumverbindungen und eines Kokatalysators, der aus einem Gemisch eines oder mehrerer Eisenoxide und/oder Eisenoxidhydrate und aktivierenden chloridhaltigen Zusätzen besteht.The present invention relates to an improved process for the preparation of urethanes (carbamic acid esters) by reacting organic nitro compounds with carbon monoxide and organic compounds containing at least one hydroxyl group in the presence of palladium and / or palladium compounds and a cocatalyst which consists of a mixture of one or more iron oxides and / or Iron oxide hydrates and activating chloride-containing additives.

Organische Isocyanate werden großtechnisch im allgemeinen durch Umsetzung der entsprechenden Amine mit Phosgen hergestellt. Wegen der Giftigkeit des Phosgens ist man seit geraumer Zeit bestrebt, einen großtechnisch gangbaren Syntheseweg zu organischen Isocyanaten aufzufinden, bei welchem sich die Verwendung des Phosgens erübrigt. Ein derartiger Syntheseweg besteht in der Umsetzung von organischen Nitroverbindungen mit Kohlenmonoxid und organischen Hydroxylverbindungen zu den entsprechenden Urethanen und deren anschließende Spaltung in Isocyanat und Hydroxylgruppen aufweisende Verbindungen, wobei vor der Spaltung auch eine Modifizierung des als Zwischenprodukt erhaltenen Urethans denkbar ist. So ist es beispielsweise möglich, das aus Nitrobenzol, Kohlenmonoxid und Äthanol zugängliche Phenylurethan zunächst mit Formaldehyd zum Bisurethan des 4,4'-Diisocyanatodiphenylmethans umzusetzen, um das so erhaltene Zwischenprodukt unter Abspaltung des Äthanols in 4,4'-Diisocyanatodiphenylmethan zu überführen.Organic isocyanates are generally produced on an industrial scale by reacting the corresponding amines with phosgene. Because of the toxicity of the phosgene, efforts have been made for some time to find an industrially feasible synthetic route to organic isocyanates in which the use of the phosgene is unnecessary. Such a synthetic route consists in the reaction of organic nitro compounds with carbons monoxide and organic hydroxyl compounds to give the corresponding urethanes and their subsequent cleavage into compounds having isocyanate and hydroxyl groups, it also being possible to modify the urethane obtained as an intermediate before the cleavage. For example, it is possible to first react the phenylurethane accessible from nitrobenzene, carbon monoxide and ethanol with formaldehyde to the bisurethane of 4,4'-diisocyanatodiphenylmethane in order to convert the intermediate product thus obtained to 4,4'-diisocyanatodiphenylmethane with elimination of the ethanol.

Die Spaltung von Urethanen in die entsprechenden Isocyanate und Hydroxylgruppen aufweisenden Verbindungen ist beispielsweise in der DE-OS 2 421 503 bzw. in den in dieser Literaturstelle abgehandelten Vorveröffentlichungen beschrieben.The cleavage of urethanes into the corresponding compounds containing isocyanates and hydroxyl groups is described, for example, in DE-OS 2 421 503 and in the prior publications dealt with in this reference.

Für die Herstellung der Urethane sind in der Patentliteratur im wesentlichen zwei Katalysatortypen beschrieben. So wird beispielsweise in den DE-Osen 2 343 826, 2 614 101 und 2 623 694 die Umsetzung von organischen Nitroverbindungen mit Kohlenmonoxid und Alkoholen zu Urethanen in Gegenwart von Selen oder Selenverbindungen beschrieben. Man erhält dabei sowohl mit Mono- als auch mit Dinitroverbindungen gute Urethan-Ausbeuten. Die Selenverbindungen, insbesondere die während der Reaktion intermediär entstehenden Organoselenverbindungen und Selenwasserstoff, sind außerordentlich giftig und müssen bei der Aufarbeitung quantitativ, z.B. durch chemische Reaktion, entfernt werden, wodurch eine aufwendige chemische Aufarbeitungsstufe resultiert, welche die Wirtschaftlichkeit des Verfahrens in Frage stellt.Essentially two types of catalysts are described in the patent literature for the production of the urethanes. For example, DE - Osen 2 343 826, 2 614 101 and 2 623 694 describes the reaction of organic nitro compounds with carbon monoxide and alcohols to urethanes in the presence of selenium or selenium compounds. Good urethane yields are obtained with both mono- and dinitro compounds. The selenium compounds, in particular the organoselic compounds and hydrogen selenium formed during the reaction, are extremely toxic and have to be worked up be removed quantitatively, for example by chemical reaction, which results in a complex chemical work-up step which questions the economics of the process.

In den DE-OSen 1 568 044 und 2 603 574 werden als Katalysatoren Edelmetalle, insbesondere Palladium, in Gegenwart von Lewissäuren beschrieben. Als besonders wirksame Lewissäure wird wasserfreies Eisen(III)-chlorid angegeben. Man erhält mit diesen Katalysatoren zwar gute Urethan-Ausbeuten, bezogen auf die eingesetzte Nitroverbindung. In Bezug auf die eingesetzte Hydroxyverbindung sind die Ausbeuten jedoch unbefriedigend. So erhält man bei Verwendung von Äthanol als Hydroxykomponente hohe Anteile von Diäthyläther, dessen Bildung durch die sauren Eigenschaften der Lewissäure verursacht werden. Gleichzeitig beobachtet man bei Anwendung dieser Edelmetall/Lewissäure-Katalysatoren Korrosion der als Reaktionsbehälter eingesetzten Edelstahlautoklaven. Durch Zusatz organischer Basen, wie beispielsweise Pyridin (DE-OS 2 603 574) kann die Korrosion zwar weitgehend zurückgedrängt werden, die Ätherbildung ist jedoch in Gegenwart dieser Katalysatorsysteme noch untragbar hoch. Ein weiterer Nachteil dieser Katalysatorsysteme liegt in ihrer schlechten Rückführbarkeit, da die angewandten Lewissäuren in Gegenwart der eingesetzten Hydroxyverbindungen nicht ausreichend stabil sind.DE-OSes 1 568 044 and 2 603 574 describe noble metals, in particular palladium, as catalysts in the presence of Lewis acids. Anhydrous iron (III) chloride is stated to be a particularly effective Lewis acid. With these catalysts, good urethane yields are obtained, based on the nitro compound used. With regard to the hydroxy compound used, the yields are unsatisfactory. Thus, when using ethanol as the hydroxy component, high proportions of diethyl ether are obtained, the formation of which is caused by the acidic properties of Lewis acid. At the same time, corrosion of the stainless steel autoclaves used as reaction vessels is observed when these noble metal / Lewis acid catalysts are used. By adding organic bases, such as pyridine (DE-OS 2 603 574), the corrosion can be largely suppressed, but the formation of ether is still prohibitively high in the presence of these catalyst systems. Another disadvantage of these catalyst systems is their poor traceability, since the Lewis acids used are not sufficiently stable in the presence of the hydroxy compounds used.

Es wurde nun überraschend gefunden, daß die Umsetzung von organischen Nitroverbindungen mit Kohlenmonoxid und mindestens eine Hydroxygruppe enthaltenden organischen Verbindungen zu Urethanen in der flüssigen Phase bei erhöhter Temperatur und erhöhtem Druck in Gegenwart von Palladium und/oder Palladiumverbindungen und einem Kokatalysator besonders selektiv, sowohl in Bezug auf die eingesetzte organische Nitroverbindung, als auch in Bezug auf die organische Hydroxyverbindung durchgeführt werden kann, wenn man als Kokatalysatoren Gemische von Eisenoxiden und/oder Eisenoxidhydraten und aktivieren.- den chloridhaltigen Zusätzen verwendet.It has now surprisingly been found that the reaction of organic nitro compounds with carbon monoxide and organic compounds containing at least one hydroxyl group to form urethanes in the liquid phase at elevated temperature and pressure in the presence of palladium and / or palladium compounds and a cocatalyst is particularly selective, both in relation to on the organic nitro compound used, and also in relation to the organic hydroxy compound, if mixtures of iron oxides and / or hydrated iron oxides and activating - the chloride-containing additives are used as cocatalysts.

Gegenstand der vorliegenden Erfindung ist somit ein Verfahren zur Herstellung von Urethanen durch Umsetzung organischer Nitroverbindungen mit Kohlenmonoxid und mindestens eine Hydroxylgruppe enthaltenden organischen Verbindungen in der flüssigen Phase bei erhöhter Temperatur und erhöhtem Druck in Gegenwart von Palladium und/oder Palladium-Verbindungen und einem Kokatalysator, dadurch gekennzeichnet, daß man als Kokatalysatoren sowohl

  • (i) Eisenoxide und/oder Eisenoxidhydrate als auch
  • (ii) anionisch, als Chlorid gebundenes Chlor enthaltende Verbindungen von Elementen der dritten bis fünften Hauptgruppe oder ersten bis achten Nebengruppe des Periodensystems der Elemente mit Ausnahme von Eisen- oxychlorid und/oder und Palladiumchlorid tert. Ammoniumchloride einsetzt.
The present invention thus relates to a process for the preparation of urethanes by reacting organic nitro compounds with carbon monoxide and organic compounds containing at least one hydroxyl group in the liquid phase at elevated temperature and pressure in the presence of palladium and / or palladium compounds and a cocatalyst, thereby characterized in that both cocatalysts
  • (i) Iron oxides and / or iron oxide hydrates as well
  • (ii) anionic compounds containing chlorine-bonded chlorine of elements of the third to fifth main group or first to eighth subgroup of the Periodic Table of the Elements with the exception of iron oxychloride and / or and palladium chloride tert. Ammonium chloride used.

Als oxidische Eisenkomponente (i) können z.B. Oxide und Oxidhydrate des zwei- und dreiwertigen Eisens in reiner Form oder als Gemisch eingesetzt werden, wie beispielsweise Eisen(II)-oxid, Eisen(II)-hydroxid, Eisen(III)-hydroxid, α -Fe2O3, δ-Fe2O3, Fe3O4, α-FeO-OH, β-Fe0-OH, δ-FeO-OH. Be- sonders bevorzugt sind die Oxide und Oxidhydrate des dreiwertigen Eisens. Die oxidische Eisenkomponente wird in Konzentrationen von 0,1 bis 20 Gew.-%, vorzugsweise von 1-5 Gew.-%, bezogen auf das Reaktionsgemisch inklusive gegebenenfalls mitverwendeter Lösungsmittel, eingesetzt.As the oxidic iron component (i), for example, oxides and Oxide hydrates of divalent and trivalent iron can be used in pure form or as a mixture, such as, for example, iron (II) oxide, iron (II) hydroxide, iron (III) hydroxide, α -Fe 2 O 3 , δ-Fe 2 O 3 , Fe 3 O 4 , α-FeO-OH, β-Fe0-OH, δ-FeO-OH. Be - are Sonder preferably the oxides and hydrated oxides of trivalent iron. The oxidic iron component is used in concentrations of 0.1 to 20% by weight, preferably 1-5% by weight, based on the reaction mixture, including any solvents that may be used.

Als Kokatalysatorkomponente (ii) werden beim erfindungsgemäßen Verfahren anionisch als Chlorid gebundenes Chlor enthaltende Verbindungen von Elementen der dritten bis fünften Hauptgruppe oder der ersten bis achten Nebengruppe des Periodensystems der Elemente mit Ausnahme von Eisenoxychlorid, die gegebenenfalls auch als Komplexsalze vorliegen können und/oder Hydrochloride von tertiären organischen Aminen eingesetzt.As cocatalyst component (ii) in the process according to the invention, chlorine-containing compounds containing elements of the third to fifth main group or the first to eighth subgroup of the periodic table of elements with the exception of iron oxychloride, which may also be present as complex salts and / or hydrochlorides of, are chlorine-bonded chlorine tertiary organic amines used.

Beispiele geeigneter Chloride sind AlCl3, SnCl2, 2H20, SbCl3, CuCl2, ZnCl2, CeCl3, TiOCl2, VCl3, CrCl3, MnCl2, FeCl2 nH2O (n = 0,1,2,4,6), α - und β-Fe2(OH)3Cl, FeCl2 · n Pyridin (n=2/3, 1,2,4), FeCl2 · n Picolin (n = 1,4) u.ä. Komplexverbindungen.Examples of suitable chlorides are AlCl 3 , SnCl 2 , 2H 2 0, SbCl 3 , CuCl2, ZnCl 2 , CeCl 3 , TiOCl 2 , VCl 3 , CrCl 3 , MnCl 2 , FeCl 2 nH 2 O (n = 0.1.2 , 4,6), α - and β-Fe 2 (OH) 3 Cl, FeCl 2 · n pyridine (n = 2/3, 1,2,4), FeCl 2 · n picoline (n = 1,4) etc. Complex compounds.

Als Hydrochloride tertiärer Amine eignen sich insbesondere Hydrochloride von beliebigen unter den Reaktionsbedingungen inerten tertiären Aminen des Molgewichts 59-10.000, vorzugsweise 59 - 300 . Es sind sowohl Hydrochloride aliphatischer als auch cycloaliphatischer, aromatischer araliphatischer oder heterocyclischer tert. Amine geeignet. Ebenfalls geeignet sind Hydrochloride von tert. Aminen, welches unter den Reaktionsbedingungen inerte Substituenten, wie beispielsweise Halogen-, Alkenyl-, Cyano-, Aldehyd-, Alkoxy-, Phenoxy-, Thioalkoxy-, Thiophenoxy-, Carbamyl-, Carboalkoxy- und/oder Thiocarbamyl-Substituenten aufweisen. Beispiele geeigneter tertiärer Amine sind Trimethylamin, Triäthylamin, Triprcpylamin, Tributylamin, cycloaliphatische tertiäre Amine, wie N,N-Dimethylcyclohexylamin, N,N-Di- äthylcyclohexylamin, 1,4-Diazabicyclo(2,2,2)oetan, aromatische tertiäre Amine wie N,N-Dimethylanilin, N,N-Diäthylanilin, sowie heteroaromatische tertiäre Amine wie Pyridin, Chinolin, Isochinolin, Chinaldin, Lepidin, pyrolysiertes Polyacrylnitril oder Polyvrinylpyridin.Particularly suitable hydrochlorides of tertiary amines are hydrochlorides of any tertiary amines having a molecular weight of 59-10,000, preferably 59-300, which are inert under the reaction conditions. There are both hydrochloride aliphatic and cycloaliphatic, aromatic araliphatic or heterocyclic tert. Suitable amines. Hydrochlorides of tert. Amines which have substituents which are inert under the reaction conditions, such as, for example, halogen, alkenyl, cyano, aldehyde, alkoxy, phenoxy, thioalkoxy, thiophenoxy, carbamyl, carboalkoxy and / or thiocarbamyl substituents. Examples of suitable tertiary amines are trimethylamine, triethylamine, triprcpylamine, tributylamine, cycloaliphatic tertiary amines, such as N, N-dimethylcyclohexylamine, N, N-diethylcyclohexylamine, 1,4-diazabicyclo (2,2,2) oetane, aromatic tertiary amines such as N, N-dimethylaniline, N, N-diethylaniline, and heteroaromatic tertiary amines such as pyridine, quinoline, isoquinoline, quinaldine, lepidine, pyrolyzed polyacrylonitrile or polyvinylridine.

Zu den bevorzugten Kokatalysator-Komponenten (ii) ge-hören Eisen(II)-chlorid-Verbindungen der oben beispielhaft genannten Art und die beispielhaft genannten tert. Ammoniumchloride insbesondere das Hydrochlorid des Pyridins.The preferred co-catalyst components (ii) g of iron (II) e-listen chloride compounds of the type exemplified above and tert those exemplified. Ammonium chlorides, especially the hydrochloride of pyridine.

Die Kokatalysator-Komponenten (ii) werden vorteilhafterweise in Konzentrationen von 0,05 bis 10 Gew.-%, insbesondere von O,1 bis 5 Gew.-%, bezogen auf Reaktionsgemisch inklusive gegebenenfalls mitverwendetem Lösungsmittel, zugesetzt. Man kann die reinen Verbindungen verwenden, jedoch auch Gemische der beispielhaft genannten Verbindungen einsetzen.The cocatalyst components (ii) are advantageously added in concentrations of 0.05 to 10% by weight, in particular 0.1 to 5% by weight, based on the reaction mixture, including any solvent which may be used set. The pure compounds can be used, but mixtures of the compounds mentioned by way of example can also be used.

Die wesentliche Katalysatorenkomponente sind Palladiumsalze der nachstehend beispielhaft genannten Art, die vorzugsweise dem Reaktionsgemisch als solche zugegeben werden. Auch metallisches Palladium kann dem Reaktionsgemisch zugegeben werden, da durch das chloridaktivierte Eisenoxid eine Oxydation des metallischen Palladiums in Palladium(II)-Verbindungen stattfindet. Auch die Mitverwendung eines inerten Trägers, beispielsweise eines Aluminiumoxid-Trägers für das Palladium ist denkbar. Besonders vorteilhaft wird Palladium als im Reaktionsgemisch lösliche Verbindung zugegeben. Als Verbindungen sind beispielsweise Palladiumchlorid, Palladiumbromid, Palladiumjodid, Natriumtetrachloropalladat, Kaliumtetrachloropalladat, Natriumtetrabromopalladat, Natriumtetrajodopalladat, Kaliumtetrajodopalladat, Palladiumacetat, Palladiumacetylacetonat u.ä. lösliche Palladium- verbindungen geeignet. Ein besonders bevorzugtes Palladiumsalz ist Palladiumchlorid. Palladium oder die Palladiumverbindungen werden bevorzugt in Konzentrationen, bezogen auf das Reaktionsgemisch, inklusive gegebenenfalls mitverwendetem Lösungsmittel von 0,0001 bis 0,1 Gew.-%, insbesondere von 0,0002 bis 0,01 Gew.-%, berechnet als metallisches Palladium, zugegeben. Bei niedrigeren Palladium-Konzentrationen wird die Reaktionsgeschwindigkeit zu gering. Höhere Palladium-Konzentrationen sind zwar möglich, jedoch wegen der möglichen Edelmetallverluste unwirtschaftlich, zumal eine weitere Steigerung der Urethanausbeuten nicht mehr erfolgt. Es ist gerade einer der wesentlichen Vorteile des erfindungsgemäßen Verfahrens, daß es die Herstellung der Urethane in ausgezeichneten Ausbeuten bei gleichzeitiger Verwendung von nur äußerst geringen Mengen an Palladium-Verbindungen gestattet.The essential catalyst components are palladium salts of the type exemplified below, which are preferably added as such to the reaction mixture. Metallic palladium can also be added to the reaction mixture, since the chloride-activated iron oxide causes oxidation of the metallic palladium in palladium (II) compounds. The use of an inert carrier, for example an aluminum oxide carrier for the palladium, is also conceivable. Palladium is particularly advantageously added as a compound soluble in the reaction mixture. Examples of compounds include palladium chloride, palladium bromide, palladium iodide, sodium tetrachloropalladate, potassium tetrachloropalladate, sodium tetrabromopalladate, sodium tetraiodopalladate, potassium tetraiodopalladate, palladium acetate, palladium acetylacetonate and the like. soluble palladium compounds suitable. A particularly preferred palladium salt is palladium chloride. Palladium or the palladium compounds are preferably in concentrations, based on the reaction mixture, including any solvent used, from 0.0001 to 0.1% by weight, in particular from 0.0002 to 0.01% by weight, calculated as metallic palladium, admitted. The reaction rate becomes too slow at lower palladium concentrations. Higher palladium concentrations are possible, but uneconomical due to the possible loss of precious metals, especially since the urethane yields are no longer increased. It is just one of the main advantages of the invention Process that allows the production of urethanes in excellent yields while using only extremely small amounts of palladium compounds.

Gemäß einer besonderen Ausführungsform des erfindungsgemäßen Verfahrens werden als weitere KatalysatorenKomponente Basen, vorzugsweise tertiäre Amine, mitverwendet. Diese Mitverwendung von tertiären Aminen erhöht die Selektivität bezüglich möglicher unerwünschter Nebenreaktionen der als Reaktionspartner eingesetzten organischen Hydroxy-Verbindungen.According to a particular embodiment of the process according to the invention, bases, preferably tertiary amines, are also used as further catalyst components. This concomitant use of tertiary amines increases the selectivity with regard to possible undesirable side reactions of the organic hydroxy compounds used as reactants.

Geeignete organische Basen sind insbesondere beliebige, unter den Reaktionsbedingungen inerte tert. Amine des Molekulargewichtsbereiches 59 - 10 000, vorzugsweise 59 - 300. Sowohl aliphatische als auch cycloaliphatische, aromatische, araliphatische oder heterocyclische tert. Amine sind geeignet. Ebenfalls geeignet sind derartige tert. Amine, welche unter den Reaktionsbedingungen inerte Substituenten, wie beispielsweise Halogen-, Alkenyl-, Cyano-, Aldehyd-, Alkoxy-, Phenoxy-, Thioalkoxy, Thiophenoxy-, Carbamyl-, Carboalkoxy- und/oder Thiocarbamyl-Substituenten aufweisen. Beispiele geeigneter tertiärer Amine sind Trimethylamin, Triäthylamin, Tripropylamin, Tributylamin, u.ä., cycloaliphatische tertiäre Amine, wie N,N-Dimethylcyclohexylamin, N,N-Diäthylcyclohexylamin, 1,4-Diazabicyclo(2,2,2)octan u.ä., aromatische tertiäre Amine wie N,N-Dimethylanilin, N,N-Diäthylanilin, sowie heteroaromatische tertiäre Amine, wie Pyridin, Chinolin, Isochinolin, Chinaldin, Lepidin, pyrolysiertes Polyacrylnitril oder Polyvinylpyridin.Suitable organic bases are in particular any tert, inert under the reaction conditions. Amines in the molecular weight range 59-10,000, preferably 59-300. Both aliphatic and cycloaliphatic, aromatic, araliphatic or heterocyclic tert. Amines are suitable. Such tert are also suitable. Amines which have substituents which are inert under the reaction conditions, such as, for example, halogen, alkenyl, cyano, aldehyde, alkoxy, phenoxy, thioalkoxy, thiophenoxy, carbamyl, carboalkoxy and / or thiocarbamyl substituents. Examples of suitable tertiary amines are trimethylamine, triethylamine, tripropylamine, tributylamine and the like, cycloaliphatic tertiary amines such as N , N -dimethylcyclohexylamine, N, N-diethylcyclohexylamine, 1,4-diazabicyclo (2,2,2) octane and the like. Ä., Aromatic tertiary amines such as N, N-dimethylaniline, N, N-diethylaniline, and heteroaromatic tertiary amines such as pyridine, quinoline, isoquinoline, quinaldine, lepidine, pyrolyzed polyacrylonitrile or polyvinylpyridine.

Die tertiären Amine können in Konzentrationen von 0,01 bis 10 Gew.-%, insbesondere 0,1 bis 5 Gew.-%, bezogen auf das Reaktionsgemisch inklusive gegebenenfalls mitverwendetem Lösungsmittel, zugesetzt werden.The tertiary amines can be added in concentrations of 0.01 to 10% by weight, in particular 0.1 to 5% by weight, based on the reaction mixture, including any solvent used.

Ausgangsverbindungen für das erfindungsgemäße Verfahren sind beliebige organische Nitroverbindungen, d.h. beliebige Nitrogruppen aufweisende, ansonsten unter den Bedingungen des erfindungsgemäßen Verfahrens inerte organische Verbindungen mit mindestens einer aliphatisch, cycloaliphatisch und/oder aromatisch gebundenen Nitrogruppe, eines im allgemeinen zwischen 61 und 400, vorzugsweise 123 und 262 liegenden Molekulargewichts, sowie beliebige, mindestens eine Hydroxygruppe enthaltende organische Verbindungen, beispielsweise substituierte oder unsubstituierte, aliphatische, cycloaliphatische und/oder aromatische Mono- oder Polyhydroxyverbindungen, eines im allgemeinen zwischen 32 und 228, vorzugsweise 32 und 102 liegenden Molekulargewichts.Starting compounds for the process according to the invention are any organic nitro compounds, i.e. any nitro groups, otherwise organic compounds which are inert under the conditions of the process according to the invention and have at least one aliphatic, cycloaliphatic and / or aromatic nitro group, a molecular weight generally between 61 and 400, preferably 123 and 262, and any organic compounds containing at least one hydroxyl group Compounds, for example substituted or unsubstituted, aliphatic, cycloaliphatic and / or aromatic mono- or polyhydroxy compounds, of a molecular weight generally between 32 and 228, preferably 32 and 102.

Beispielsweise können folgende aromatische Nitroverbindungen eingesetzt werden: Nitrobenzol, o-Dinitrobenzol, m-Dinitrobenzol, p-Dinitrobenzol, o-Chlor-nitrobenzol, m-Chlor-nitrobenzol, o-Chlor-nitrobenzol, o-Nitrotoluol, m-Nitrotoluol, p-Nitrotoluol, 2,3-Dinitrotoluol, 2,4-Dinitrotolüol, 2,5-Dinitrotoluol, 2,6-Dinitrotoluol, 3,4-Dinitrotoluol, 3-Nitro-o-xylol, 4-Nitro-o-xylol, 2-Nitro-m-xylol, 4-Nitro-m-xylol, 5-Nitro-m-xylol, Nitro-p-xylol, 3,4-Dinitro-o-xylol, 3,5-Dinitro-o-xylol, 3,6-Dinitro-c-xylol, 4,5-Dinitro-o-xylol, 2,4-Dinitro-m-xylol, 2,5-Dinitro- m-xylol, 4,5-Dinitro-m-xylol, 4,6-Dinitro-m-xylol, 2,3-Dinitro-p-xylol, 2,6-Dinitro-p-xylol, 1-Nitronaphthalin, 2-Nitronaphthalin, Dinitronaphthaline, Nitroanthracene, Nitrodiphenyle, Bis-(nitrophenyl)-methane, Bis-(nitrophenyl)-thioäther, Bis-(nitrophenyl)-sulfone, Nitrodiphenoxyalkane, Nitrophenothiazine.For example, the following aromatic nitro compounds can be used: nitrobenzene, o-dinitrobenzene, m-dinitrobenzene, p-dinitrobenzene, o-chloro-nitrobenzene, m-chloro-nitrobenzene, o-chloro-nitrobenzene, o-nitrotoluene, m-nitrotoluene, p- nitrotoluene, 2,3-dinitrotoluene, 2,4-Dinitrotolüol, 2,5-dinitrotoluene, 2,6-D initrotoluol, 3,4-dinitrotoluene, 3-nitro-o-xylene, 4-nitro-o-xylene, 2 -Nitro-m-xylene, 4-nitro-m-xylene, 5-nitro-m-xylene, nitro-p-xylene, 3,4-dinitro-o-xylene, 3,5-dinitro-o-xylene, 3 , 6-dinitro-c-xylene, 4,5-dinitro-o-xylene, 2,4-dinitro-m-xylene, 2,5- D initro-m-xylene, 4,5-dinitro-m-xylene, 4,6-dinitro-m-xylene, 2,3-dinitro-p-xylene, 2,6-dinitro-p-xylene, 1-nitronaphthalene, 2-nitronaphthalene, dinitronaphthalenes, Nitroanthracenes, nitrodiphenyls, bis (nitrophenyl) methanes, bis (nitrophenyl) thioethers, bis (nitrophenyl) sulfones, nitrodiphenoxyalkanes, nitrophenothiazines.

Als cycloaliphatische Nitroverbindungen seien genannt: Nitrocyclobutan, Nitrocyclopentan, Nitrocyclohexan, 1,2-Dinitracyclohexan, 1,3-Dinitrocyclohexan, 1,4-Dinitrocyclohexan, Bis-(nitrocyclohexyl)-methane.The following may be mentioned as cycloaliphatic nitro compounds: nitrocyclobutane, nitrocyclopentane, nitrocyclohexane, 1,2-dinitracyclohexane, 1,3-dinitrocyclohexane, 1,4-dinitrocyclohexane, bis- (nitrocyclohexyl) methane.

Beispielhaft für die Gruppe der Nitroalkane seien genannt: Nitromethan, Nitroäthan, 1-Nitropropan, 2-Nitropropan, Nitrobutane, Nitropentane, Nitrohexane, Nitrodecane, Nitrocetane, 1,2-Dinitroäthan, 1,2-Dinitropropan, 1,3-Dinitropropan, Dinitrobutane, Dinitropentane, Dinitrohexane, Dinitrodecane, Phenylnitromethan, Bis-(nitromethyl)-cyclohexane, Bis-(nitromethyl)-benzole, ω-Nitrocarbonsäurenitrile.Examples of the group of nitroalkanes are: nitromethane, nitroethane, 1-nitropropane, 2-nitropropane, nitrobutane, nitropentane, nitrohexane, nitrodecane, nitrocetane, 1,2-dinitroethane, 1,2-dinitropropane, 1,3-dinitropropane, dinitrobutane , Dinitropentane, Dinitrohexane, Dinitrodecane, Phenylnitromethan, Bis- (nitromethyl) -cyclohexane, Bis- (nitromethyl) -benzenes, ω-Nitrocarbonsonitrile.

Besonders beovrzugte Nitroverbindungen für das erfindungsgemäße Verfahren sind aromatische Nitroverbindungen wie insbesondere Nitrobenzol, 1,3-Dinitrobenzol, 2,4-Dinitrotoluol, 2,6-Dinitrotoluol, Dinitronaphthaline wie z.B. 1,5-Dinitronaphthalin oder 2,4'- bzw. 4,4'-Dinitrodiphenylmethan.Particularly preferred nitro compounds for the process according to the invention are aromatic nitro compounds such as in particular nitrobenzene, 1,3-dinitrobenzene, 2,4-dinitrotoluene, 2,6-dinitrotoluene, dinitronaphthalenes such as e.g. 1,5-dinitronaphthalene or 2,4'- or 4,4'-dinitrodiphenylmethane.

Zu den erfindungsgemäß geeigneten Hydroxygruppen enthaltenden organischen Verbindungen zählen einwertige Alkohole, mehrwertige Alkohole, einwertige Phenole und mehrwertige Phenole.Organic compounds containing hydroxyl groups suitable according to the invention include monovalent ones Alcohols, polyhydric alcohols, monohydric phenols and polyhydric phenols.

Die Alkohole umfassen lineare oder verzweigte Alkanole, Cycloalkanole, Alkenole, Cycloalkenole, Aralkylalkohole und ähnliches, jeder ein- oder mehrwertig. Diese Alkohole können einen Substituenten enthalten, der Sauerstoff, Stickstoff, Schwefel oder ein Halogenatom enthält, beispielsweise eine Halogen-, Sulfoxid-, Sulfon-, Amin-, Amid-, Carbonyl- oder Carbonsäureestergruppe. Beispielhaft seien folgende einwertigen Alkohole genannt: Methylalkohol, Äthylalkohol, Propanol, Isopropanol, Butanol, Pentanol, Hexanol, Cyclohexanol, Benzylalkohol. Geeignete mehrwertige Alkohole sind beispielsweise: Äthylenglykol, Diäthylenglykol, Propylenglykol, Dipropylenglykol, Glycerin, Hexantriol und ähnliche sowie höher funktionelle Polyole. Bevorzugt werden einwertige aliphatische Alkohole mit 1-6 Kohlenstoffatomen und besonders bevorzugt Äthylalkohol eingesetzt.The alcohols include linear or branched alkanols, cycloalkanols, alkenols, cycloalkenols, aralkyl alcohols and the like, each mono- or polyvalent. These alcohols may contain a substituent containing oxygen, nitrogen, sulfur or a halogen atom, for example a halogen, sulfoxide, sulfone, amine, amide, carbonyl or carboxylic acid ester group. The following monohydric alcohols may be mentioned by way of example: methyl alcohol, ethyl alcohol, propanol, isopropanol, butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol. Suitable polyhydric alcohols are, for example: ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, glycerol, hexanetriol and the like, and more highly functional polyols. Monohydric aliphatic alcohols with 1-6 carbon atoms are preferred, and ethyl alcohol is particularly preferred.

Zu den erfindungsgemäß geeigneten Phenolen zählen beispielsweise Phenol, Chlorphenole, Kresole, Äthylphenole, Propylphenole, Butylphenole oder höhere Alkylphenole, Brenzcatechin, Resorcin, 4,4'-Dihydroxydiphenylmethan, Bisphenol-A, Anthranol, Phenanthrol, Pyrogallol oder Phloroglucin.The phenols suitable according to the invention include, for example, phenol, chlorophenols, cresols, ethylphenols, propylphenols, butylphenols or higher alkylphenols, pyrocatechol, resorcinol, 4,4'-dihydroxydiphenylmethane, bisphenol-A, anthranol, phenanthrol, pyrogallol or phloroglucin.

Die organischen Hydroxy-Verbindungen werden bei der Durchführung des erfindungsgemäßen Verfahrens im allgemeinen in solchen Mengen eingesetzt, daß bei Verwendung von Mononitroverbindungen als Ausgangsmaterial ein Äquivalentverhältnis zwischen Nitrogruppen und Hydroxylgruppen von 1:0,5 bis 1:100, vorzugsweise 1:1 bis 1:100 und bei Verwendung von Dinitroverbindungen ein Äquivalentverhältnis zwischen Nitrogruppen und Hydroxylgruppen von 1: bis 1:100 vorliegt.The organic hydroxy compounds are generally carried out when carrying out the process according to the invention mean used in such amounts that when using mononitro compounds as the starting material an equivalent ratio between nitro groups and hydroxyl groups of 1: 0.5 to 1: 100, preferably 1: 1 to 1: 100 and when using dinitro compounds an equivalent ratio between nitro groups and hydroxyl groups of 1: to 1: 100 is present.

Besonders bevorzugt werden die bevorzugten Alkohole im Überschuß eingesetzt, wobei der nicht umgesetzte Überschuß als Reaktionsmedium dient.The preferred alcohols are particularly preferably used in excess, the unreacted excess serving as the reaction medium.

Das Kohlenmonoxid wird im allgemeinen in einer Menge eingesetzt, die 1 bis 30 Mol Kohlenmonoxid pro Mol an umzusetzenden Nitrogruppen entspricht, wobei im allgemeinen das Kohlenmonoxid in den vorzugsweise beim erfindungsgemäßen Verfahren eingesetzten Druckreaktor eingepreßt wird.The carbon monoxide is generally used in an amount corresponding to 1 to be converted nitro groups to 30 moles of carbon monoxide per M ol, being pressed in general, the carbon monoxide in the preferably used in the present process pressure reactor.

Die erfindungsgemäße Umsetzung kann in Geqsnwart oder in Abwesenheit eines Lösungsmittels durchgeführt werden. Im allgemeinen dient die vorzugsweise im Überschuß eingesetzte organische Hydroxylverbindung als Lösungsmittel. Die Mitverwendung inerter Lösungsmittel, die bis zu 80 Gew.-% des gesamten Reaktionsansatzes ausmachen können, ist jedoch auch möglich. Die Menge des Lösungsmittels muß, gleichgültig ob es sich um im Überschuß eingesetzte Hydroxylverbindung oder um inertes Lösungsmittel handelt, so bemessen sein, daß die Reaktionswärme der exothermen Urethanbildung ohne unzulässige Temperaturerhöhung abgeführt werden kann. Im allgemeinen wird daher das erfindungsgemäße Verfahren unter Verwendung einer Konzentration an Nitroverbindungen von 5-30 Gew.-%, vorzugsweise 5-20 Gew.-%, bezogen auf das Gesamtreaktionsgemisch inklusive dem Lösungsmittel durchgeführt.The reaction according to the invention can be carried out in the presence or in the absence of a solvent. In general, the organic hydroxyl compound, which is preferably used in excess, serves as the solvent. The additional use of inert solvents, up to 80 wt -.%, However, can account for the entire reaction mixture, is also possible. The amount of the solvent, irrespective of whether it is an excess hydroxyl compound or an inert solvent, must be such that that the heat of reaction of the exothermic urethane formation can be dissipated without undue increase in temperature. In general, the process according to the invention is therefore carried out using a concentration of nitro compounds of 5-30% by weight, preferably 5-20% by weight, based on the total reaction mixture including the solvent.

Brauchbare Lösungsmittel sind gegen die Reaktionskomponenten und das Katalysatorsystem inerte Lösungsmittel, wie beispielsweise aromatische, cycloaliphatische und aliphatische Kohlenwasserstoffe, die gegebenenfalls durch Halogen substituiert sein können, wie Benzol, Toluol, Xylol, Chlorbenzol, Dichlorbenzol, Trichlorbenzol, Chlornaphthalin, Cyclohexan, Methylcyclohexan, Chlorcyclohexan, Methylenchlorid, Tetrachlorkohlenstoff, Tetrachlcräthan, Trichlor-trifluoräthan u.ä. Verbindungen.Usable solvents are solvents which are inert to the reaction components and the catalyst system, such as aromatic, cycloaliphatic and aliphatic hydrocarbons, which may optionally be substituted by halogen, such as benzene, toluene, xylene, chlorobenzene, dichlorobenzene, trichlorobenzene, chloronaphthalene, cyclohexane, methylcyclohexane, chlorine Methylene chloride, carbon tetrachloride, carbon tetrachloride, trichlorotrifluoroethane and the like Links.

Die Reaktionstemperatur liegt im allgemeinen zwischen 100°C und etwa 300°C, insbesondere zwischen 1300C und 250°C und besonders vorteilhaft im Bereich von 140°C bis 220°C. Der Druck muß so bemessen sein, daß stets das Vorliegen einer flüssigen Phase gewährleistet ist und liegt im allgemeinen im Bereich von 5 bis 500 bar, besonders vorteilhaft im Bereich von 30 bis 300 bar bei Reaktionstemperatur. Je nach eingesetzter Nitroverbindung bzw. Hydioxyverbindung beträgt die für quantitativem Umsatz benötigte Reaktionszeit zwischen wenigen Minuten und mehreren Stunden.The reaction temperature is generally between 100 ° C. and about 300 ° C., in particular between 1300 ° C. and 250 ° C. and particularly advantageously in the range from 140 ° C. to 220 ° C. The pressure must be such that the presence of a liquid phase is always ensured and is generally in the range from 5 to 500 bar, particularly advantageously in the range from 30 to 300 bar at the reaction temperature. Depending on the nitro compound or the hydroxy compound used, the amount for quantita Reactive sales required reaction time between a few minutes and several hours.

Die Umsetzung der Nitroverbindungen mit den Hydroxy- verbindungen und Kohlenmonoxid zu Urethanen kann diskontinuierlich oder kontinuierlich durchgeführt werden.The reaction of the nitro compounds with the hydroxy compounds and carbon monoxide to form urethanes can be carried out batchwise or continuously.

Die diskontinuierliche Umsetzung kann im Hochdruckautoklaven mit geringen Mengen homogen gelöstem Palladiumsalz, einem ausreichenden Überschuß Eisenoxid und/oder Eisenoxidhydrat und einer ausreichenden Menge der beispielhaft genannten Kokatalysator-Komponenten (ii) durchgeführt werden. Die im Reaktionsmedium unlöslichen Eisenoxide, bzw. Eisenoxidhydrate werden vorzugsweise in Form eines feinen Pulvers zugegeben, die aktivierenden Zusatzstoffe (ii) vorzugsweise in Form einer homogenen alkoholischen Lösung. Die Verteilung der nicht gelösten überschüssigen Eisenoxid-Verbindungen kann beispielsweise durch kräftiges Rühren oder durch Umpumpen des Reaktionsgemisches erfolgen. Die exotherme Reaktionswärme kann z.B. durch intern eingebaute Kühlaggregate oder im Falle des Umpumpens auch über einen externen Wärmeaustauscher abgeführt werden. Die Aufarbeitung und Katalysatorrückführung kann je nach Löslichkeit des erzeugten Urethans im Reaktionsgemisch auf verschiedene Weise erfolgen. Bei leicht löslichen Urethanen kann beispielsweise nach beendeter Reaktion die Hauptmenge des bei tiefen Temperaturen schwerlöslichen Kokatalysatorgemisches samt dem größten Teil des adsor- bierten Palladiums und des organischen Aminsalzes vom Reaktionsprodukt abgetrennt werden, beispielsweise durch Filtration oder Zentrifugieren, und in eine neue Umsetzung von Nitroverbindungen, Hydroxyverbindungen und Kohlenmonoxid wieder zurückgeführt werden. Das flüssige Reaktionsgemisch kann auf übliche Weise, z.B. durch fraktionierte Destillation, in Lösungsmittel, in die reinen Urethane und gegebenenfalls kleine Mengen von.Nebenprodukten aufgetrennt werden, wobei diese Trennung diskontinuierlich oder kontinuierlich erfolgen kann. Im Destillationsrückstand sind oft kleine Mengen der im Reaktionsgemisch gelösten Kokatalysator-Komponente (ii) und/oder Spuren von Palladiumverbindungen enthalten, die wieder in die Umsetzung zurückgeführt werden können.The batchwise reaction can be carried out in a high-pressure autoclave with small amounts of homogeneously dissolved palladium salt, a sufficient excess of iron oxide and / or iron oxide hydrate and a sufficient amount of the cocatalyst components (ii) mentioned by way of example. The iron oxides or iron oxide hydrates which are insoluble in the reaction medium are preferably added in the form of a fine powder, the activating additives (ii) preferably in the form of a homogeneous alcoholic solution. The undissolved excess iron oxide compounds can be distributed, for example, by vigorous stirring or by pumping around the reaction mixture. The exothermic heat of reaction can be dissipated, for example, by internally installed cooling units or, in the case of pumping, by an external heat exchanger. The work-up and recycling of the catalyst can take place in various ways depending on the solubility of the urethane produced in the reaction mixture. With slightly soluble urethanes the majority of the poorly soluble at low temperatures Kokatalysatorgemisches together with the greatest part of the Adsor example, after completion of the reaction - based palladium and the organic amine salt are separated from the reaction product, for example by filtration or centrifugation, and are recycled into a new reaction of nitro compounds, hydroxy compounds and carbon monoxide. The liquid reaction mixture can be separated in a customary manner, for example by fractional distillation, in solvent, into the pure urethanes and, if appropriate, small amounts of by-products, which separation can be carried out batchwise or continuously. The distillation residue often contains small amounts of the cocatalyst component (ii) dissolved in the reaction mixture and / or traces of palladium compounds, which can be returned to the reaction.

Im Falle von im Lösungsmittel bzw. überschüssiger Hydroxyverbindung schwer löslichen Urethanen kann die Aufarbeitung des Reaktionsgemisches in abgeänderter Weise erfolgen. Beispielsweise wird nach Entspannung unter Druck und höherer Temperatur, bei welchen die Urethane noch gelöst sind, jedoch das Katalysatorsystem Palladium/Kokatalysatorgemisch weitgehend ausfällt, die Hauptmenge Katalysator abfiltriert oder abzentrifugiert und dann durch Temperaturerniedrigung das schwerlösliche Urethan, gegebenenfalls zusammen mit geringen Mengen schwerlöslicher Nebenprodukte und restlichem Katalysator, auskristallisiert. Die Mutterlauge, die außer Lösungsmittel, bzw. der als Lösungsmittel angewandten überschüssigen organischen Hydroxyverbindung, noch geringe Mengen Nebenprodukte, gelöstes Urethan und gegebenenfalls gelöste Kokatalysator-Komponenten (ii) enthält, kann direkt oder nach vorheriger Entfernung leichtsiedender Nebenprodukte beispielsweise durch Destillation, in die Umsetzung der Nitroverbindungen mit den Hydroxyverbindungen und Kohlenmonoxid zurückgeführt werden, wcbei die dem vorherigen Umsatz entsprechende Menge Nitroverbindung und Hydroxyverbindung ergänzt wird. Höhersiedende Nebenprodukte, welche nicht durch Kristallisation entfernt werden, können durch destillative Aufarbeitung eines aliquoten Teiles der Mutterlauge als Destillationrückstand kontinuierlich aus dem Rückführstrom entfernt werden. Das ausgefallene Rohurethan kann beispielsweise durch Kristallisation aus einem das Urethan bei höheren Temperaturen lösenden, die Nebenprodukte und die Katalysatorreste jedoch nicht lösenden Lösungsmittel wie beispielsweise Isooktan, Benzol, Toluol, Xylol, Chlorbenzol, Dichlorbenzol rekristallisiert werden. Die bei erhöhter Temperatur unlöslichen Rückstände können durch Oxidation in Eisenoxid und ein aus den organischen Verunreinigungen resultierendes Abgas, das im wesentlichen aus Kohlendioxid, Sauerstoff, Stickstoff und gegebenenfalls leicht flüchtigen organischen Ver-' unreinigungen besteht, umgewandelt werden. Das Abgas kann je nach Zusammensetzung direkt in die Atmosphäre abgelassen werden oder zusätzlich einer katalytischen Nachverbrennung zugeführt werden, in welcher restliche Verunreinigungen oxidativ entfernt werden. Das aus dem Rückstand erhaltene Eisenoxid, das gegebenenfalls noch geringe Mengen Palladium und/oder Palladiumverbindung enthalten kann, wird wieder in die Umsetzung der Nitroverbindungen mit Hydroxyverbindungen und Kohlenmonoxid zurückgeführt.In the case of urethanes which are sparingly soluble in the solvent or excess hydroxy compound, the reaction mixture can be worked up in a modified manner. For example, after relaxation under pressure and a higher temperature, at which the urethanes are still dissolved, but the catalyst system palladium / cocatalyst mixture largely fails, the main amount of catalyst is filtered off or centrifuged and then the sparingly soluble urethane, if appropriate together with small amounts of sparingly soluble by-products and the rest, is reduced by lowering the temperature Catalyst crystallized out. The mother liquor, in addition to solvents, or the excess organic hydroxy compound used as solvent, still small amounts of by-products, ge contains dissolved urethane and optionally dissolved cocatalyst components (ii) can be recycled directly or after the removal of low-boiling by-products, for example by distillation, into the reaction of the nitro compounds with the hydroxy compounds and carbon monoxide, which is supplemented by the amount of nitro compound and hydroxy compound corresponding to the previous conversion . Higher-boiling by-products which are not removed by crystallization can be continuously removed from the recycle stream as a distillation residue by working up an aliquot of the mother liquor by distillation. The precipitated crude urethane can be recrystallized, for example, by crystallization from a solvent which dissolves the urethane at higher temperatures but does not dissolve the by-products and the catalyst residues, such as isooctane, benzene, toluene, xylene, chlorobenzene, dichlorobenzene. The residues which are insoluble at elevated temperature can be converted by oxidation into iron oxide and a waste gas resulting from the organic impurities, which essentially consists of carbon dioxide, oxygen, nitrogen and optionally highly volatile organic impurities. Depending on the composition, the exhaust gas can be discharged directly into the atmosphere or additionally fed to a catalytic post-combustion, in which residual impurities are removed by oxidation. That from the Residue obtained iron oxide, which may still contain small amounts of palladium and / or palladium compound, is returned to the reaction of the nitro compounds with hydroxy compounds and carbon monoxide.

Die kontinuierliche Umsetzung kann in einer Kesselkaskade, einem Rohrbündelreaktor, mehrerer hintereinander geschalteten Schlaufenreaktoren, in einem oder einer Serie hintereinander geschalteten adiabaten Reaktionsrohren durchgeführt werden. Die Wärmeabführung erfolgt beispielsweise entweder intern durch eingebaute Kühlaggregate, extern über einen Rohrbündelwärmetauscher oder adiabatisch über die Wärmekapazität des Reaktionsgemisches mit nachfolgender Abkühlung in externen Kühlaggregaten.The continuous reaction can be carried out in a boiler cascade, a tube bundle reactor, a plurality of loop reactors connected in series, in one or a series of adiabatic reaction tubes connected in series. The heat is dissipated, for example, either internally through built-in cooling units, externally via a tube bundle heat exchanger, or adiabatically via the heat capacity of the reaction mixture with subsequent cooling in external cooling units.

Die weitere Aufarbeitung kann wie oben beschrieben erfolgen, wobei sowohl eine kontinuierliche als auch eine diskontinuierliche Arbeitsweise angewandt werden kann.Further processing can be carried out as described above, it being possible to use both a continuous and a discontinuous procedure.

Im Falle der bevorzugten Verwendung der erfindungsgemäßen Verfahrensprodukte als Zwischenprodukte zur Herstellung der entsprechenden Isocyanate ist ihre Reindarstellung oft überflüssig. Zur weiteren Verarbeitung kann es vielmehr ausreichend sein, die nach Abfiltrieren des Katalysators und gegebenenfalls Abdestillieren des Lösungsmittels anfallende Rohprodukte in die Weiterverarbeitung einzusetzen.In the case of the preferred use of the process products according to the invention as intermediates for the preparation of the corresponding isocyanates, their pure preparation is often superfluous. Rather, for further processing, it may be sufficient to obtain the raw products obtained after filtering off the catalyst and, if appropriate, distilling off the solvent used in further processing.

Das Verfahren wird durch die folgenden Beispiele illustriert, ohne damit die Erfindung auf die in den Beispielen gegebenen Bedingungen einzuschränken.The process is illustrated by the following examples, without thereby restricting the invention to the conditions given in the examples.

Beispiel 1example 1

In einen 0,7 1 Autoklaven aus rostfreiem Stahl wurden eine Lösung von 50 g Nitrobenzol in 200 g Äthanol zusammen mit 0,005 g Palladiumchlorid (19 ppm), 10,0 g α-Fe2O3 (3 , 8 Gew.-%), 3 , 0 g FeC1 2 4 H20 (1,1 Gew.-%) und 2,5 g Pyridin (0,9 Gew.-%) eingebracht und 120 bar Kohlenmonoxid bei Raumtemperatur aufgepreßt. Der Autoklaveninhalt wurde auf 1800C aufgeheizt, wcbei sich ein maximaler Druck von 145 bar einstellte, und 2 h bei dieser Temperatur belassen. Der Druck betrug nun 100 bar. Nun wurde auf Raumtemperatur abgekühlt, das Reaktionsgas über eine Kühlfalle entspannt und der flüssige Autoklaveninhalt zusammen mit der in der Kühlfalle abgeschiedenen Flüssigkeit gaschromatografisch analysiert. Der Nitrobenzol-Umsatz betrug 100 %. Die Selektivität an Phenylurethan (Äthyl-N-phenylcarbamidsäureester), bezogen auf Nitrobenzol, lag ebenfalls bei 100 %.Into a 0.7 1 stainless steel autoclave a solution of 50 g of nitrobenzene in 200 g of ethanol were combined with 0.005 g of palladium chloride (19 ppm), 10.0 g of α-Fe 2 O 3 (3, 8 wt .-%) introduced, 3, 0 g FEC1 2 4 H 2 0 (1.1 wt .-%) and 2.5 g of pyridine (0.9 wt .-%) and 120 bar pressed carbon monoxide at room temperature. The autoclave contents were heated to 180 0 C, a maximum pressure of 145 bar was wcbei, and left for 2 h at this temperature. The pressure was now 100 bar. Now the mixture was cooled to room temperature, the reaction gas was released via a cold trap and the liquid autoclave contents together with the liquid separated in the cold trap were analyzed by gas chromatography. The nitrobenzene conversion was 100%. The selectivity for phenyl urethane (ethyl-N-phenyl carbamic acid ester), based on nitrobenzene, was also 100%.

Beispiel 2Example 2

Es wurde wie im Beispiel 1 gearbeitet, jedoch als Katalysator 2,6 Gew.-% α-Fe2O3 und 4,2 Gew.-% Pyridiniumchlorid eingesetzt; Pyridin selbst wurde nicht zugegeben. Auch hier betrug der Nitrobenzolumsatz 100 %; die Selektivität an Phenylurethan, bezogen auf Nitrobenzol, betrug 95 %.The procedure was as in Example 1, but 2.6% by weight of α-Fe 2 O 3 and 4.2% by weight of pyridinium chloride were used as catalysts; Pyridine itself was not added. Here, too, the nitrobenzene conversion was 100%; the selectivity of phenyl urethane, based on nitrobenzene, was 95%.

Beispiel 3Example 3

Es wurde wie in Beispiel 1 gearbeitet, jedoch anstelle von Nitrobenzol 7,0 Gew.-%, bezogen auf Gesamtgemisch, an 2,4-Dinitrotoluo (DNT) zu 7,0 Gew.-% eingesetzt. Der DNT-Umsatz betrug 100 %; die Selektivität an Bisurethan war - bezogen auf DNT - 96 %; die effektive Reaktionszeit betrug lediglich 40 min.The procedure was as in Example 1, but instead of nitrobenzene, 7.0% by weight, based on the total mixture, of 2,4-dinitrotoluo (DNT) was used at 7.0% by weight. The DNT conversion was 100%; the selectivity of bisurethane was - based on DNT - 96%; the effective response time was only 40 min.

Beispiel 4Example 4

Es wurde wie in Beispiel 1 gearbeitet, jedoch kein Eisenoxid, sondern lediglich 1,2 Gew.-% FeCl2 · 4 H2O eingesetzt.The procedure was as in Example 1, but no iron oxide, but only 1.2% by weight of FeCl 2 .4H 2 O was used.

Der Nitrobenzol-Umsatz betrug nur 25 % (bei gleichgebliebener Selektivität).The nitrobenzene conversion was only 25% (with the same selectivity).

Dieser Versuch beweist die Notwendigkeit der Eisenoxid-Zugabe.This experiment demonstrates the need to add iron oxide.

Beispiel 5Example 5

Es wurde wie in Beispiel 1 gearbeitet, jedooh kein FeCl2 · 4 H2O, sondern lediglich 3,8 Gew.-% α -Fe2O3 eingesetzt.The procedure was as in Example 1, jedooh no FeCl 2 · 4 H 2 O, but only 3.8 wt .-% α-Fe 2 O used. 3

Der Nitrobenzolumsatz betrug nur 1 %.The nitrobenzene conversion was only 1%.

Dieser Versuch beweist die Notwendigkeit, das α -Fe2O3 mit einem Chlorid-Zusatz (beispielsweise in Form des FeCl2 · 4 H20 oder des Pyridiniumchlorids) zu aktivieren.This experiment demonstrates the need to activate the α -Fe 2 O 3 with a chloride additive (for example in the form of FeCl 2 · 4 H 2 0 or pyridinium chloride).

Claims (10)

1. Verfahren zur Herstellung von Urethanen durch Umsetzung organischer Nitroverbindungen mit Kohlenmonoxid und mindestens eine Hydroxygruppe enthaltenden organischen Verbindungen in der flüssigen Phase bei erhöhter Temperatur und erhöhtem Druck in Gegenwart von Palladium und/oder Palladium-Verbindungen und einem Kokatalysator, dadurch gekennzeichnet, daß man als Kokatalysator sowohl (i) Eisenoxide und/oder Eisenoxidhydrate als auch (ii) anionisch, als Chlorid gebundenes Chlor enthaltende Verbindungen von Elementen der dritten bis fünften Hauptgruppe oder ersten bis achten Nebengruppe des Periodensystems der Elemente mit Aus- nahme von Eisenoxychlorid und Palladiumchlorid, und/oder tert. Ammoniumchloride einsetzt.. 1. A process for the preparation of urethanes by reacting organic nitro compounds with carbon monoxide and organic compounds containing at least one hydroxyl group in the liquid phase at elevated temperature and pressure in the presence of palladium and / or palladium compounds and a cocatalyst, characterized in that as Cocatalyst both (i) Iron oxides and / or iron oxide hydrates as well (ii) anionic, chlorine-containing chlorine-containing compounds of elements of the third to fifth main group or first to eighth subgroup of the periodic table of the elements with the exception of iron oxychloride and palladium chloride, and / or tert. Ammonium chloride used .. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß man als Komponente (i) Oxide und/oder Oxidhydrate des dreiwertigen Eisens verwendet.2. The method according to claim 1, characterized in that oxides and / or oxide hydrates of trivalent iron are used as component (i). 3. Verfahren nach Anspruch 1 und 2, dadurch gekennzeichnet, daß man als Komponente (ii) Eisen (II)-Chlorid und/oder Eisen(II)-chlorid-Komplexe verwendet.3. The method according to claim 1 and 2, characterized in that iron (II) chloride and / or iron (II) chloride complexes are used as component (ii). 4. Verfahren nach Anspruch 1 bis 2, dadurch gekennzeichnet, daß man als Komponente (ii) Hydrochloride tertiärar Amine verwendet.4. The method according to claim 1 to 2, characterized in that tertiary amines are used as component (ii) hydrochloride. 5. Verfahren nach Anspruch 1 bis 4, dadurch gekennzeichnet, daß man als zusätzliche Katalysator-Komponente tertiäre Amine mitverwendet.5. The method according to claim 1 to 4, characterized in that tertiary amines are used as an additional catalyst component. 6. Verfahren nach Anspruch 4, dadurch gekennzeichnet, daß als Hydrochlorid eines tertiären Amins Pyridinhydrochlorid eingesetzt wird.6. The method according to claim 4, characterized in that pyridine hydrochloride is used as the hydrochloride of a tertiary amine. 7. Verfahren nach Anspruch 1 bis 6, dadurch gekennzeichnet, daß man als Nitroverbindung Nitrobenzol oder Dinitrotoluol verwendet.7. The method according to claim 1 to 6, characterized in that nitrobenzene or dinitrotoluene is used as the nitro compound. 8. Verfahren nach Anspruch 1 bis 7, dadurch gekennzeichnet, daß man als mindestens eine Hydroxygruppe enthaltende organische Verbindung einen einwertigen aliphatischen Alkohol mit 1 bis 6 Kohlenstoffatomen verwendet.8. The method according to claim 1 to 7, characterized in that a monohydric aliphatic alcohol having 1 to 6 carbon atoms is used as the organic compound containing at least one hydroxy group. 9. Verfahren nach Anspruch 1 bis 8, dadurch gekennzeichnet, daß man die Umsetzung im Temperaturbereich zwischen 130°C und 250°C durchführt.9. The method according to claim 1 to 8, characterized in that one carries out the reaction in the temperature range between 130 ° C and 250 ° C. 10. Verfahren nach Anspruch 1 bis 9, dadurch gekennzeichnet, daß man die Umsetzung im Druckbereich zwischen 5 und 500 bar durchführt.10. The method according to claim 1 to 9, characterized in that one carries out the reaction in the pressure range between 5 and 500 bar.
EP80100271A 1979-02-02 1980-01-21 Process for the preparation of urethanes Expired EP0014845B1 (en)

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JPS5772954A (en) * 1980-10-23 1982-05-07 Mitsubishi Chem Ind Ltd Preparation of aromatic carbamic acid ester
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